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Notes: Summary S-100 protein, a soluble protein restricted to the nervous system, was measured by complement fixation in 51 neurogenic and non-neurogenic tumors produced by either methylnitrosourea or ethylnitrosourea in three different strains of rats. Nineteen of the 51 neurogenic tumors were neoplasms of the central nervous system (18 of the brain, 1 of the spinal cord). They were diagnosed morphologically as 5 mixed gliomas, 4 anaplastic gliomas, 4 glioependymomas, 1 ependymoma, 3 gliosarcomas, and 2 unclassified tumors. With the exception of one anaplastic glioma and one gliosarcoma, all other central nervous system tumors contained S-100 protein, ranging from 0.005–0.13% of the total 35000 g supernatant protein. S-100 protein was also demonstrated in 21 of the 22 tumors of the peripheral nervous system, originating from the trigeminal nerves, the spinal roots, and from peripheral nerves. The average S-100 protein content of these tumors was 0.2% (range 0.02–1.6%). A possible correlation between S-100 protein content and tumor differentiation must be evaluated. S-100 protein was detected in only one of 10 neoplasms morphologically classified as non-neurogenic (7 sarcomas, 2 carcinomas, and 1 hemangioendothelioma). On the basis of its S-100 protein content, one tumor was reclassified as a neurosarcoma. The sensitivity and the high degree of specificity of the S-100 protein assay makes it a useful biochemical tool for the identification of neurogenic tumors. The presence of S-100 protein must be considered as a definitive indication for neural cell participation in neoplastic growth.

Notes: Summary A series of 24 human acoustic neurinomas from 24 patients has been assayed for several biochemical parameters characteristic of the nervous system. S 100 protein, 2′, 3′-cyclic nucleotide 3′-phosphohydrolase activity, and the myelin lipids galactosylceramide and sulfogalactosylceramide (sulfatide). Myelin basic protein was not detected. These findings further support the neuroectodermal origin of the human acoustic neurinoma, and provide additional biochemical markers for further study.

Notes: Summary Biopsy specimens from 23 human brain tumors have been analyzed for the nervous system specific protein S-100 and the membrane-associated enzyme 2′,3′-cyclic nucleotide 3′-phosphohydrolase (CpNase). Biopsy specimens from an additional seven brain tumors were tested for either S-100 or CpNase alone. All astrocytomas and glioblastomas tested were found to contain S-100 and CpNase although there does not appear to be a strong correlation between the levels of these two markers in the 14 such tumors assayed for both. S-100 levels varied over a 19-fold range while CpNase varied over a 835-fold range. Postoperative survival in the astrocytoma and glioblastoma patients showed only a weak correlation with either tumor CpNase or S-100 levels. Two acoustic neurinomas, two oligodendrogliomas, one mixed glioma, and one choroid plexus papilloma were also assayed and found to have detectable levels of both S-100 and CpNase with the acoustic neurinomas and the mixed glioma having relatively high levels of each marker. All six meningiomas tested had low levels of CpNase. S-100 assays in three benign meningiomas were negative, while low levels of this protein were found in the one malignant meningioma tested. Tissue cultures were grown out from biopsy specimens of additional human brain tumors and tested at confluency for S-100. Of 15 astrocytoma and glioblastoma cultures tested, three had easily detectable amounts of S-100, two appeared to contain trace levels and ten were negative. The two acoustic neurinoma cultures tested were positive for S-100 while all three oligodendroglioma cultures were negative.

Notes: In order to help clarify the controversially discussed dermal uptake properties of micronized titanium dioxide (TiO 〈inlineGraphic alt="inline image" href="urn:x-wiley:01425463:ICS211924:ICS_211924_mu1" location="equation/ICS_211924_mu1.gif" extraInfo="missing"/〉), we conducted extensive in vitro dermal absorption studies with ’Franz-type’ diffusion cells on excised porcine skin. After biopsies and chemical fixation, the overall localization of TiO 〈inlineGraphic alt="inline image" href="urn:x-wiley:01425463:ICS211924:ICS_211924_mu2" location="equation/ICS_211924_mu2.gif" extraInfo="missing"/〉 in the skin was analyzed by means of transmission electron microscopy (TEM). The lateral and vertical distribution of TiO 〈inlineGraphic alt="inline image" href="urn:x-wiley:01425463:ICS211924:ICS_211924_mu3" location="equation/ICS_211924_mu3.gif" extraInfo="missing"/〉 within the stratum corneum (SC) was investigated by tape stripping and subsequent scanning electron microscopy (SEM) in combination with energy dispersive X-ray analysis (EDXA).TiO 〈inlineGraphic alt="inline image" href="urn:x-wiley:01425463:ICS211924:ICS_211924_mu4" location="equation/ICS_211924_mu4.gif" extraInfo="missing"/〉 was found exclusively on the outermost SC layer. The surface deposit, as displayed by TEM, featured clearly distinguishable agglomerates as well as single particles with a characteristic cubic shape and a primary particle size of about 20–50 nm. Concurrently, SEM/EDXA micrographs first showed an even distribution of TiO 〈inlineGraphic alt="inline image" href="urn:x-wiley:01425463:ICS211924:ICS_211924_mu5" location="equation/ICS_211924_mu5.gif" extraInfo="missing"/〉 on the skin surface. After 10-fold stripping, however, TiO 〈inlineGraphic alt="inline image" href="urn:x-wiley:01425463:ICS211924:ICS_211924_mu6" location="equation/ICS_211924_mu6.gif" extraInfo="missing"/〉 was found to be localized only in the furrows and not on the partially removed ridges of the skin surface. SEM/EDXA micrographs of the adhesive tape strips revealed a characteristic pattern of stripped material and free regions. This pattern was an imprint of the skin’s topography. Hence, tape stripping initially removed TiO 〈inlineGraphic alt="inline image" href="urn:x-wiley:01425463:ICS211924:ICS_211924_mu7" location="equation/ICS_211924_mu7.gif" extraInfo="missing"/〉 and SC layers only from the ridges and not from the deeper furrows. Continued stripping increasingly yielded material from the deeper contours of the SC surface. TiO 〈inlineGraphic alt="inline image" href="urn:x-wiley:01425463:ICS211924:ICS_211924_mu8" location="equation/ICS_211924_mu8.gif" extraInfo="missing"/〉 was found only in traces in the upper part of the follicle without any evidence of uptake into the follicular epithelium. This indicates that there is not any relevant penetration via the follicular route.We conclude that due to the microtopography of the skin, the strip number normally does not reflect the SC layer number. Accordingly, tape stripping results should always be interpreted with care, especially in the case of topically applied particles, as even higher numbers of subsequent strips may still sample material from the outermost SC layer of the deeper furrows, which could be interpreted falsely as penetrated material. Our results clearly demonstrate that TiO 〈inlineGraphic alt="inline image" href="urn:x-wiley:01425463:ICS211924:ICS_211924_mu9" location="equation/ICS_211924_mu9.gif" extraInfo="missing"/〉 homogeneously and completely covers the outermost SC layer. It is neither delivered to the SC nor to the underlying skin layers when applied topically to porcine skin in vitro in the cosmetic vehicle used here. These findings underscore the safety of this micronized inorganic UV filter.

Notes: Abstract: Galactolipid metabolism was investigated as a function of development in primary cultures initiated from 19–21-day-old dissociated fetal rat brain. Significant amounts of galactocerebrosides, sulfatides, and monogalactosylglycerides were synthesized and accumulated by 8 days in culture. Thereafter the synthetic rates and levels of these galactolipids increased rapidly, reaching maximal values ∼22–29 days in culture. Galactolipids containing nonhydroxy or 2-hydroxy fatty acid were both synthesized at approximately equal rates. The initial rates of synthesis, investigated at 15, 29, and 50 days in culture, were three- to fivefold higher for galactocerebrosides than for sulfatides and two- to threefold higher than for monogalactosylglycerides. The total number of cells staining with antisera against galactocerebroside of sulfatide also increased very rapidly between 8 and 22 days in culture, reaching levels of 4–5 million cells per seeded fetal brain. The amount of galactocerebroside or sulfatide per cell stained with the corresponding antiserum increased severalfold from 10 to 27 days in culture and remained high until at least 36 days in culture (the latest time point examined). Thus, the temporal expression of galactolipid accumulation in the cell cultures was comparable to that occurring in rat brain, but some important quantitative reductions in the levels of accumulation per cell in culture were noted. In addition, in contrast to normal brain in which galactolipid synthetic rates are reduced after the period of most active myelination, in culture both synthesis and turnover of these galactolipids remained high, suggestive of a partial arrest in myelin maturation.

Notes: Abstract: Cholesterol ester hydrolase activities previously have been identified in brain and linked to the production of myelin, which has very low levels of esterified cholesterol. We have studied two cholesterol ester hydrolase activities (termed the pH 6.0 and pH 7.2 activities) in cultures derived from 19- to 21-day-old dissociated fetal rat brains and in developing rat brain. In vivo the levels of both the pH 6.0 and pH 7.2 activities began to increase by about 10 postnatal days, reached maximal levels at 20 days (20 and 1.5 nmol/h/mg protein, respectively), and thereafter remained nearly constant (pH 6.0) or decreased somewhat before becoming constant (pH 7.2). In contrast, in the cultures the pH 6.0 cholesterol ester hydrolase activity was low until 21 days in culture (DIC; 20 nmol/h/mg protein), increased to a peak activity at 31 DIC (60 nmol/h/mg protein), remained high for 24 days, and finally decreased (18 nmol/h/mg protein at 63 DIC); the pH 7.2 cholesterol ester hydrolase activity was very low until 20 DIC, increased to a peak activity at 31 days (3 nmol/h/mg protein), and thereafter decreased to a lower level (2 nmol/h/mg protein) that was maintained for about 24 days before decreasing (0.7 nmol/h/mg protein at 63 DIC). Therefore, (a) the time courses of appearance of both cholesterol ester hydrolase activities were delayed by 10–14 days relative to that seen in vivo, and (b) the specific activities observed in the cultures were transiently two- to three-fold higher than in rat brain, but then declined to levels characteristic of whole brain homogenates. Subcellular fractionation of the cultures demonstrated that the pH 7.2 cholesterol ester hydrolase activity, along with myelin basic protein and 2′,3′-cyclic nucleotide-3′-phosphohydrolase activity, was enriched in a membrane fraction collected at an interface between 0.32 M and 0.9 M sucrose; the pH 6.0 cholesterol ester hydrolase activity, in contrast, was enriched in the microsomal fraction.

Notes: Abstract: Evidence is presented for the immunological identification of a developmental antigen appearing at a critical point in the oligodendroglial lineage. Specifically, monoclonal antibody A007 recognizes cells in the oligodendrocyte lineage at two distinct stages. Analyses of purified lipid standards and lipid extracts from galactocerebroside-positive (GalC+) oligodendrocytes by enzyme-linked immunosorbent assay, lipid dot blot, and immuno-TLC demonstrated that A007 recognizes sulfatide (SUL) and seminolipid. However, neither 35SO4 incorporation into SUL nor SUL accumulation could be detected in A007-positive cells lacking galactocerebroside (i.e., A007+GalC− progenitor cells) present early in development. These data suggest that A007 also recognizes an antigen, named proligodendroblast antigen (POA), that appears during the late stage of oligodendrocyte progenitor development prior to the expression by oligodendrocytes of SUL and GalC. We have previously reported that monoclonal antibody O4 also recognizes not only SUL and seminolipid, but in addition an antigen that appears prior to the expression of SUL and galactocerebroside. In the present study all A007+ cells were also O4+ (and vice versa), and the developmental patterns of the two antibodies appeared to be identical. We conclude that (1) A007 is similar or identical to O4 with respect to its antigenic specificity, and (2) during oligodendrocyte lineage progression both antibodies react first with antigen POA on the surface of the oligodendrocyte progenitor cell prior to the expression of SUL [i.e., A007+O4+(POA+)SUL−GalC− proligodendroblasts], and only later with SUL as terminally differentiating oligodendrocytes emerge (i.e., A007+-O4+SUL+GalC+ oligodendrocytes).

Notes: Clonal cell line D6P2T, subcloned from an ethylnitrosourea-induced tumor line D6 of the rat peripheral nervous system, has been characterized with particular attention to galactolipid metabolism. Galactosylcerebroside and sulfatide synthesis and expression on the cell surface are highly regulated in D6P2T cells by mechanisms involving serum-and cyclic AMP-mediated pathways. These cells also express 2′,3′-cyclic nucleotide 3′-phosphohydrolase (Wolfgram protein Wla) and laminin. In contrast, myelin basic protein and antigen HNK-1 were not detected. Line D6P2T appears to be a semi-differentiated Schwann cell model, which offers interesting possibilities for studies of galactolipid synthesis, transport, and sorting.